Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

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Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.StringTokenizer;


public class A {

	static StringTokenizer st;
	static BufferedReader br;
	static PrintWriter pw;
	public static void main(String[] args) throws IOException {
		br = new BufferedReader(new InputStreamReader(System.in));
		pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
		int n = nextInt();
		int m = nextInt();
		int[][]a = new int[n+1][m+1];
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= m; j++) {
				a[i][j] = nextInt();
			}
		}
		int[]r = new int[n+1], c = new int[m+1];
		int[]ansR = new int[n+1], ansC = new int[m+1];
		int INF = (int) 1e9;
		int ans = INF;
		for (int r1 = 0; r1 <= 500; r1++) {
			r[1] = r1;
			for (int i = 1; i <= m; i++) {
				c[i] = a[1][i] - r[1];
			}
			for (int i = 2; i <= n; i++) {
				r[i] = a[i][1] - c[1];
			}
			boolean ok = true;
			for (int i = 1; i <= n; i++) {
				if (!ok)
					break;
				if (r[i] < 0) {
					ok = false;
					break;
				}
				for (int j = 1; j <= m; j++) {
					if (c[j] < 0) {
						ok = false;
						break;
					}
					if (r[i]+c[j] != a[i][j]) {
						ok = false;
						break;
					}
				}
			}
			if (ok) {
				int curAns = 0;
				for (int i = 1; i <= n; i++) {
					curAns += r[i];
				}
				for (int i = 1; i <= m; i++) {
					curAns += c[i];
				}
				if (curAns < ans) {
					ans = curAns;
					ansR = r.clone();
					ansC = c.clone();
				}
			}
		}
		if (ans==INF)
			pw.println(-1);
		else {
			pw.println(ans);
			for (int i = 1; i <= n; i++) {
				for (int j = 1; j <= ansR[i]; j++) {
					pw.println("row "+i);
				}
			}
			for (int i = 1; i <= m; i++) {
				for (int j = 1; j <= ansC[i]; j++) {
					pw.println("col "+i);
				}
			}
		}
		pw.close();
	}
	private static int nextInt() throws IOException {
		return Integer.parseInt(next());
	}
	private static long nextLong() throws IOException {
		return Long.parseLong(next());
	}
	private static double nextDouble() throws IOException {
		return Double.parseDouble(next());
	}
	private static String next() throws IOException {
		while (st==null || !st.hasMoreTokens())
			st = new StringTokenizer(br.readLine());
		return st.nextToken();
	}
}